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{{Plugin Sidebar 2|
{{Plugin Sidebar
title=Tektronix 7A42|
|manufacturer=Tektronix
summary=350 MHz four-channel logic triggered amplifier|
|series=7000-series scopes
image=Tek-7a42-crop.jpg |  
|type=7A42
caption=7A42 front view|
|summary=350 MHz four-channel logic triggered amplifier
introduced=1984 |
|image=Tektronix 7A42 front.jpg
discontinued=1990 |
|caption=7A42 front view
series=[[7000-series scopes]]|
|introduced=1984
manuals=
|discontinued=1990
* [http://w140.com/tek_7a42_service1_ocr.pdf 7A42 Service Manual Volume 1 (PDF)]
|manuals=
* [http://w140.com/tek_7a42_service2_ocr.pdf 7A42 Service Manual Volume 2 (PDF)]
* [[Media:070-4285-00.pdf|7A42 Operator Manual]] (OCR)
* 7A42 Service Manual
** [[Media:070-4286-00.pdf|070-4286-00 Volume 1]] (OCR)
** [[Media:070-4654-00.pdf|070-4654-00 Volume 2, Signature Analysis Tables]] (OCR)
<small>
'''ROM images'''
* [[Media:160-1959-00.bin|160-1959-00.bin A8U145]]
* [[Media:160-1960-00.bin|160-1960-00.bin A8U245]]
* [[Media:160-1961-00.bin|160-1961-00.bin A8U340]]
</small>
}}
}}
The '''Tektronix 7A42''' is a four-channel 350 MHz plug-in for [[7000-series scopes]].  It is a double-wide plug-in, with signal outputs and mainframe readout only using the left slot.


The '''Tektronix 7A42''' is a four-channel 350 MHz plug-in for [[7000-series scopes]].  
It was specifically designed for logic signals (TTL, ECL, CMOS) and supports triggering based on Boolean conditions of the four inputs. 
A fifth trace, "Trigger View", displays the trigger function output or external clock input.  


It was specifically designed for logic signals (TTL, ECL, CMOS) and supports triggering based on Boolean conditions of the four inputs.
There are two sets of conditions, A and B, that can be individually selected or paired in an "A then B" mode called ''nested triggering'', where the occurrence of condition A arms the trigger and condition B causes the trigger to be generated.
The trigger can be qualified by an external clock.  A trigger filter control, variable from 0-300 ns, allows events shorter than the selected length to be suppressed.  A TTL-level "reset" input will inhibit the trigger if active.


A fifth trace, "Trigger View", displays the trigger function output or external clock input.
Selected by an internal jumper, either the trigger signal, or the "A then B" interval, is available on a front-panel trigger output. This can e.g. be routed to a counter for time measurement or event counting.
 
The input V/Div setting can only be seen in the mainframe's readout. 
There is a jumper to allow the readout to work in a [[7854]] mainframe.
The trigger level is set digitally and shown on a 7-segment display.
 
Tektronix recommended the [[P6131]], 300 MHz, 10 MΩ ×10 probe, and the [[P6230]], 1.5 GHz, 450/50 Ω ×10, variable-offset probe for ECL circuits.
 
The [[067-1155-99]] calibration fixture is specific to the 7A42.


{{BeginSpecs}}
{{BeginSpecs}}
{{Spec | Bandwidth | 350 MHz}}
{{Spec | Bandwidth | 350 MHz }}
{{Spec | Deflection |
{{Spec | Deflection |
* 0.1 / 0.2 / 0.5 V/Div (TTL mode)
* 0.1 / 0.2 / 0.5 V/Div (TTL mode)
* 20 / 50 / 100 mV/Div (ECL mode)
* 20 / 50 / 100 mV/Div (ECL mode)
* each direct or through 10:1 probe}}
* each direct or through 10:1 probe
{{Spec | Input impedance | 1MΩ or 50 Ω}}
* always DC coupled }}
{{Spec | Input impedance | 1 MΩ // 15 pF or 50 Ω}}
{{Spec | Max. input voltage |
{{Spec | Max. input voltage |
* at 1 MΩ: 25 V DC+peak AC below 36 MHz, down to 3 V AC at 300 MHz
* at 1 MΩ: 25 V (DC+peak AC) below 36 MHz, down to 3 V<sub>AC</sub> at 300 MHz
* at 50Ω: 5 V RMS during any 1 ms interval}}
* at 50 Ω: 5 V<sub>RMS</sub> during any 1 ms interval}}
{{Spec | Trigger level |
{{Spec | Trigger level |
* -1.27 to +1.28 V (TTL mode) in 10 mV steps
* −1.27 to +1.28 V (TTL mode) in 10 mV steps
* -254 mV to +256 mV (ECL mode) in 2 mV steps (or ×10)}}
* −254 mV to +256 mV (ECL mode) in 2 mV steps (or ×10)}}
{{Spec | Hysteresis | 40 mV (TTL), 8 mV (ECL) (or ×10)}}
{{Spec | Hysteresis | 40 mV (TTL), 8 mV (ECL) (or ×10)}}
{{Spec | Features |
{{Spec | Features |
Line 36: Line 57:
{{Spec | Weight | 2.8 kg / 6.2 lb}}
{{Spec | Weight | 2.8 kg / 6.2 lb}}
{{EndSpecs}}
{{EndSpecs}}
==Links==
{{Documents|Link=7A42}}
==See also==
* [[067-1155-99]]
* [[A6701]]
* [[821]]


==Internals==
==Internals==
The 7A42's functions are controlled by an 8085A microprocessor.
The 7A42's functions are controlled by an [[Intel 8085]]A microprocessor, with code in three 2764 EPROMs (a fourth ROM socket is unused).  The front-panel pushbuttons are handled by an Intel 8279 keyboard controller.


Each of the four input attenuator circuits contains five [[miniature relays]]. The bistable relay coils are wired in a 4x5 matrix.
Each of the four [[119-1517-00]] input attenuator modules contains five [[148-0145-00|148-0145-00 miniature bi-stable relay actuators]].  These have four long pins plugging in to the base board, driving two solenoids that move aa yoke which is held in the last active position by a permanent magnet.  The yoke moves a pair of contact springs that directly short corresponding pads on the thick-film ceramic substrate. The relay coils are wired in a 4×5 matrix.
 
The 7A42 contains its own switch mode PSU, based on an SG3524 controller, that generates +5 V, −2 V and −5 V from the mainframe's ±50 V rails.
 
There is a [[7A42/Repairs|NiCd backup battery]] that allows the unit to retain its last configuration.
 
A 555 timer implements a 15 ms "real-time clock" and watchdog reset, another drives a beeper.
 
An internal jumper enables partial compatibility with a [[7854]] mainframe in storage mode (displaying any single channel, 1+2 in ALT, or 3+4 in ALT only).  There are no restrictions with the 7854 in analog mode.


==Pictures==
==Pictures==


<gallery>
<gallery>
Tektronix 7A42 front.jpg
Tek 7a42.jpg
Tek 7a42.jpg
Tek 7a42 1.jpg
Tek 7a42 1.jpg
Tek 7a42 2.jpg
Tek 7a42 2.jpg
Tek 7a42 3.jpg
Tek 7a42 4.jpg
Tek 7a42 fr1.jpg
Tek 7a42 fr1.jpg
Tek 7a42 fr2.jpg
Tek 7a42 fr2.jpg
Tek 7a42 fr3.jpg
Tek 7a42 fr3.jpg
Tek 7a42 fr4.jpg
Tek 7a42 fr4.jpg | display - four signal traces plus trigger view
Tek 7a42 fr5.jpg
Tek 7a42 fr5.jpg
Tek 7a42 fr6.jpg
Tek 7a42 fr6.jpg | 7A42 rear view
Tek 7a42 fr7.jpg
Tek 7a42 fr7.jpg | 7A42 top view
Tek 7a42 fr8.jpg
Tek-7A42-Bus.jpg                      | Schematic cartoon: Bus
Tek 7a42 fr9.jpg
Tek-7A42-Chirp.jpg                    | Schematic cartoon: Chirp
Tek 7a42 fr10.jpg
</gallery>
Tek 7a42 fr11.jpg
'''Internal'''
Tek 7a42 fr12.jpg
<gallery>
7A42 amplifier board.jpg  | amplifier board (one attenuator cover removed)
Tek 7a42 fr11.jpg        | amplifier board front - attenuators, amplifiers, channel switches
Tek 7a42 fr12.jpg        | amplifier board rear - channel switches, two 15 ns delay lines
7A42 attenuator 1.jpg    | attenuator, cover removed
7A42 attenuator cover.jpg | attenuator cover
7A42 attenuator 2.jpg    | attenuator, top
7A42 attenuator 3.jpg    | attenuator, one relay actuator removed
7A42 attenuator 4.jpg    | attenuator, all relay actuators removed
7A42 attenuator 5.jpg    | attenuator, all relay actuators removed
Tek 7a42 fr10.jpg        | microprocessor board
Tek 7a42 fr8.jpg         | memory backup battery on microprocessor board replaced with LiIon
Tek 7a42 fr9.jpg         | internal switch mode PSU for digital logic supplies
Tek 7a42 13.jpg
Tek 7a42 14.jpg
Tek 7a42 15.jpg
</gallery>
</gallery>


==Components==
{{Parts|7A42}}


[[Category:7000 series vertical plugins]]
[[Category:7000 series vertical plugins]]

Revision as of 02:36, 12 February 2024

Tektronix 7A42
350 MHz four-channel logic triggered amplifier
7A42 front view

Compatible with 7000-series scopes

Produced from 1984 to 1990

Manuals

ROM images

(All manuals in PDF format unless noted otherwise)
Manuals – Specifications – Links – Pictures

The Tektronix 7A42 is a four-channel 350 MHz plug-in for 7000-series scopes. It is a double-wide plug-in, with signal outputs and mainframe readout only using the left slot.

It was specifically designed for logic signals (TTL, ECL, CMOS) and supports triggering based on Boolean conditions of the four inputs. A fifth trace, "Trigger View", displays the trigger function output or external clock input.

There are two sets of conditions, A and B, that can be individually selected or paired in an "A then B" mode called nested triggering, where the occurrence of condition A arms the trigger and condition B causes the trigger to be generated. The trigger can be qualified by an external clock. A trigger filter control, variable from 0-300 ns, allows events shorter than the selected length to be suppressed. A TTL-level "reset" input will inhibit the trigger if active.

Selected by an internal jumper, either the trigger signal, or the "A then B" interval, is available on a front-panel trigger output. This can e.g. be routed to a counter for time measurement or event counting.

The input V/Div setting can only be seen in the mainframe's readout. There is a jumper to allow the readout to work in a 7854 mainframe. The trigger level is set digitally and shown on a 7-segment display.

Tektronix recommended the P6131, 300 MHz, 10 MΩ ×10 probe, and the P6230, 1.5 GHz, 450/50 Ω ×10, variable-offset probe for ECL circuits.

The 067-1155-99 calibration fixture is specific to the 7A42.

Key Specifications

Bandwidth 350 MHz
Deflection
  • 0.1 / 0.2 / 0.5 V/Div (TTL mode)
  • 20 / 50 / 100 mV/Div (ECL mode)
  • each direct or through 10:1 probe
  • always DC coupled
Input impedance 1 MΩ // 15 pF or 50 Ω
Max. input voltage
  • at 1 MΩ: 25 V (DC+peak AC) below 36 MHz, down to 3 VAC at 300 MHz
  • at 50 Ω: 5 VRMS during any 1 ms interval
Trigger level
  • −1.27 to +1.28 V (TTL mode) in 10 mV steps
  • −254 mV to +256 mV (ECL mode) in 2 mV steps (or ×10)
Hysteresis 40 mV (TTL), 8 mV (ECL) (or ×10)
Features
  • NiCd battery to preserve front-panel control status
Weight 2.8 kg / 6.2 lb

Links

Documents Referencing 7A42

Document Class Title Authors Year Links
42W-5588.pdf Application Note Advanced Triggering Techniques Roger Ensrud 1984

See also

Internals

The 7A42's functions are controlled by an Intel 8085A microprocessor, with code in three 2764 EPROMs (a fourth ROM socket is unused). The front-panel pushbuttons are handled by an Intel 8279 keyboard controller.

Each of the four 119-1517-00 input attenuator modules contains five 148-0145-00 miniature bi-stable relay actuators. These have four long pins plugging in to the base board, driving two solenoids that move aa yoke which is held in the last active position by a permanent magnet. The yoke moves a pair of contact springs that directly short corresponding pads on the thick-film ceramic substrate. The relay coils are wired in a 4×5 matrix.

The 7A42 contains its own switch mode PSU, based on an SG3524 controller, that generates +5 V, −2 V and −5 V from the mainframe's ±50 V rails.

There is a NiCd backup battery that allows the unit to retain its last configuration.

A 555 timer implements a 15 ms "real-time clock" and watchdog reset, another drives a beeper.

An internal jumper enables partial compatibility with a 7854 mainframe in storage mode (displaying any single channel, 1+2 in ALT, or 3+4 in ALT only). There are no restrictions with the 7854 in analog mode.

Pictures

Internal

Components

Some Parts Used in the 7A42

Part Part Number(s) Class Description Used in
148-0145-00 148-0145-00 Discrete component miniature bi-stable relay actuator 7A42 119-1517-00
155-0038-01 155-0038-00 155-0038-01 Monolithic integrated circuit 5-bit current source D/A converter 7A42 7D13 7D14 7M13 T4005
155-0078-00 155-0078-xx 155-0273-00 155-0274-00 Monolithic integrated circuit broadband amplifier 464 465 466 468 475 475A 475M 485 7834 7844 7854 7904 R7903 R7912 7912AD 7912HB 7104 7A16A 7A16P 7A24 7A26 7A42 067-0587-01 067-0680-00 AM503 PG502 PG508 DC510 DC5010 FG5010
155-0236-00 155-0236-00 Hybrid integrated circuit channel switch 2445 2465 2467 7A42
ICM7218 156-1621-00 156-1622-00 Monolithic integrated circuit 8-digit, 7-segment LED driver 7A42 SG5010
Intel 8085A 156-1088-00 Monolithic integrated circuit 8-bit microprocessor 308 468 4025 7A42 7D02 AFG5101 AFG5102 PFG5105
Intel 8279 156-1535-00 Monolithic integrated circuit keyboard controller 7A42 AFG5101 DM5010 FG5010 PFG5105
SG3524 156-0933-00 156-0933-01 156-1585-00 156-1585-01 Monolithic integrated circuit PWM switch-mode controller 067-1011-00 1502B 1502C 1503B 1503C 7A42 DP100